How many coronavirus cases are asymptomatic? CDC and other data range as high as 50%
The Centers for Disease Control and Prevention says up to 1 in 4 people infected with coronavirus will show no symptoms. Data from Iceland, however, show that number could be double.
CDC Director Robert Redfield said in an interview with NPR this week that many people who become infected with coronavirus can remain asymptomatic.
“That may be as many as 25%,” he said in the interview. “That’s important, because now you have individuals that may not have any symptoms that can contribute to transmission, and we have learned that in fact they do contribute to transmission.”
Redfield said with so many people not showing symptoms, there can be “significant asymptomatic transmission,” according to NPR.
People who do show symptoms, however, often are spreading the virus up to 48 hours before those symptoms appear, he said.
“This helps explain how rapidly this virus continues to spread across the country, because we have asymptomatic transmitters and we have individuals who are transmitting 48 hours before they become symptomatic,” Redfield said.
Meanwhile, Iceland is testing aggressively, according to BuzzFeed News, and that testing includes people who show no symptoms of coronavirus.
“Iceland’s population puts it in the unique position of having very high testing capabilities with help from the Icelandic medical research company deCode Genetics, who are offering to perform large scale testing,” Thorolfur Gudnason, Iceland’s chief epidemiologist, told BuzzFeed News.
With the large number of people getting tested comes mass amounts of data to help the world understand coronavirus better. One big piece of information is how many people tested positive while showing no symptoms.
Dr. Kári Stefánsson, the founder of deCode, told CNN that about 50% of people who tested positive were asymptomatic.
“What it means in my mind, is that because we are screening the general population, we are catching people early in the infection before they start showing symptoms,” Stefánsson told the news outlet.
Experts have said the U.S. is behind on testing, and that getting people tested for COVID-19 is the “biggest problem that we’re facing,” according to the Harvard Business Review.
The U.S. has run just five tests per million of its population, according to Harvard Business Review.
“The value of a test comes from its so-called specificity and sensitivity: Infected patients should be correctly identified as infected, patients who don’t carry the virus should be diagnosed as such, and people that unknowingly had the infection should be tested for immunity,” the Harvard Business Review article stated. “This helps us understand who is infected, where the infection occurred, and how the virus was transmitted.”
Coronavirus is spreading quickly in the U.S. On Wednesday, the U.S. surpassed 200,000 confirmed cases of coronavirus, doubling its total in just days, McClatchy News reported. At the beginning of March, the country had just 100 confirmed cases.
To help slow the spread of coronavirus, more than 30 states have initiated statewide stay-at-home orders, according to The New York Times.
Additionally, President Donald Trump extended coronavirus safety guidelines until April 30, McClatchy News reported. Those guidelines include social distancing, avoiding travel, limiting gatherings to 10 people and staying away from nursing homes.
This story was originally published April 1, 2020 at 8:05 PM with the headline "How many coronavirus cases are asymptomatic? CDC and other data range as high as 50%."